Ascogregarina Taiwanensis Interfere in the Performance of Aedes Albopictus and in the Susceptibility of Aedes Aegypti to Temephos and Azadirachta Indica Oil

Abstract Background: Aedes albopictus and Aedes aegypti are mosquitoes commonly adapted to tropical and subtropical regions. These vectors can transmit different types of arboviruses causing a serious concern to public health. New alternatives for the vector/arboviruses control are emerging, and in this sense the protozoan Ascogregarina taiwanensis may present potential as a biological control agent against these mosquitoes. Methods: To evaluate the effects of protozoan A. taiwanensis, mosquitoes were parasitized with a solution containing oocysts and evaluated to lifetime, fertility, fecundity for Ae. albopictus and for Ae. aegypti interaction with Azadirachta indica and Temephos. Results: In this work it was possible to observe the protozoan morphology in mosquitoes Ae. albopictus, as well its negative influence on mortality, 73% and non-parasitized was 44%. The number of eggs oviposited by parasitized females of Ae. albopictus was lower (3,490) than for the non-parasitized females (5,586). In addition, the hatchability and/or viability of these eggs were also lower for the parasitized females (63%) than the non-parasitized ones (74%). For Ae. aegypti mosquitoes, a synergism between the use of A. taiwanensis associated with a chemical insecticide and a botanical insecticide was observed. The results demonstrate that when Ae. aegypti larvae was parasitized by A. taiwanensis and exposed to the oil of Az. indica or to the organophosphate Temephos present a greater mortality. Conclusion: It was notable that A. taiwanensis can be a potential for biological control and adjuvant of insecticides. We also provide important information about the maintenance of A. taiwanensis in laboratory.

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Mosquito densoviruses: the revival of a biological control agent against urban Aedes vectors of arboviruses

10.1101/2020.04.23.055830 ◽

2020 ◽

Author(s):

Aurélie Perrin ◽

Anne-Sophie Gosselin-Grenet ◽

Marie Rossignol ◽

Carole Ginibre ◽

Bethsabée Scheid ◽

...

Keyword(s):

Biological Control ◽

Aedes Aegypti ◽

Aedes Albopictus ◽

Biological Control Agent ◽

Mortality Rates ◽

Control Agent ◽

Biocontrol Agents ◽

Specific Variation ◽

Different Strains ◽

Alternative Control Methods

ABSTRACTUrban Aedes mosquitoes are vectors of many viruses affecting human health such as Dengue, Chikungunya and Zika viruses. Insecticide resistance and environmental toxicity risks hamper the effectiveness of chemical control against these mosquito vectors. Alternative control methods, such as the use of mosquito-specific entomopathogenic viruses should be explored. Numerous studies have focused on evaluating the potential of different densoviruses species as biological control agent. However, knowledge on the extent of inter- and intra-specific variations in the susceptibility of Aedes mosquitoes to infection by different densoviruses remains insufficient. In this study, we compared infection and mortality rates induced by the Aedes albopictus densovirus 2 in different strains of Aedes albopictus and Aedes aegypti mosquitoes. The two Aedes species were different in terms of susceptibility to viral infection. Under laboratory conditions, Aedes albopictus densovirus 2 appeared more virulent for the different strains of Aedes aegypti tested than for those of Aedes albopictus. In addition, we also found significant intra-specific variation in infection and mortality rates. Thus, although even if Aedes albopictus densoviruses could be powerful biocontrol agents used in the management of urban Aedes populations, our results also call into question the use of single viral isolate as biocontrol agents.

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Observations on the predatory potential of Lutzia fuscana on Aedes aegypti larvae: implications for biological control (Diptera: Culicidae)

Fragmenta Entomologica ◽

10.4081/fe.2016.176 ◽

2016 ◽

Vol 48 (2) ◽

pp. 137

Author(s):

Soujita Pramanik ◽

Sampa Banerjee ◽

Soumyajit Banerjee ◽

Goutam K. Saha ◽

Gautam Aditya

Keyword(s):

Biological Control ◽

Aedes Aegypti ◽

Biological Control Agent ◽

Instar Larva ◽

Control Agent ◽

The Body ◽

Larval Habitats ◽

Larval Stages ◽

Augmentative Release ◽

Predatory Potential

Among the natural predators, larval stages of the mosquito Lutzia fuscana (Wiedemann, 1820) (Diptera: Culicidae) bear potential as a biological control agent of mosquitoes. An estimation of the predatory potential of the larva of L. fuscana against the larva of the dengue vector Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) was made to highlight its use in vector management. Laboratory experiments revealed that the larva of L. fuscana consumes 19 to 24 A. aegypti larvae per day, during its tenure as IV instar larva. The consumption of A. aegypti larvae was proportionate to the body length (BL) and body weight (BW) of the predatory larva L. fuscana as depicted through the logistic regressions: y = 1 / (1 + exp(-(-2.09 + 0.35*BL))) and y = 1 / (1 + exp(-(0.4+ 0.06*BW))). While the prey consumption remained comparable among the days, the net weight gained by the L. fuscana larva showed a decreasing trend with the age. On the basis of the results, it is apparent that the larva of the mosquito L. fuscana can be used in the regulation of the mosquito A. aegypti through augmentative release, particularly, in the smaller mosquito larval habitats.

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